I have a 80m free standing 1/4 vertical on 80m, over 60x 65' radials. A
coil between the feed-point and the radial plate matches the antenna.
Large ferrite beads were added to the feed-line at the feed point. The
feed-line is about 250 feet of LMR-400-DB/
Last year I decided add an inverted L for 160 to the feed point. I
couldn't get it to work well with both the 80m vertical and 160m inverted L
attached, until I added a 1:1 balun at the feed point.
The 80m element is 3" OD aluminum at the bottom and tapers to 1/4 inch at
the top, about 74 feet tall. The vertical section of the 160m inverted L
is only about 40 or so feet tall and is at approximately 20 degrees angle
to the 80m vertical before going horizontal across my yard. No other
dipoles are near it.
Performance on 80m appears unaffected, and the inverted L performs much
better than the 1/2 wave dipole I have on 160m up at 97 feet.
It has been on my to-do list to make measurements of the exact geometry of
the installation and run it through a few simulations to fully understand
what it is going on.
I think the key is the large number of radials on the ground and the balun.
Greg, N2GZ
On Wed, Dec 2, 2015 at 7:32 PM, james soto via Topband <
topband@contesting.com> wrote:
> Actually iam using an inverted L for 160 with few radials.I would like to
> build another one for 75 meters band. my questio are:1. How close they
> could be? 2. could i use the same radials existing from the 160 inverted
> L?Thankskp2bh/jimmy
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